USGS Digital Raster Graphics
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DRG Technical Information
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. GeoTIFF is a public domain extension of the TIFF standard. GeoTIFF files conform to the TIFF 6.0 base standard, but contain additional information that allows image coordinates to be transformed to ground coordinates. TIFF readers that do not recognize GeoTIFF tags can still read GeoTIFF files as ordinary TIFF data. The GeoTIFF home page is at http://www.remotesensing.org/geotiff/geotiff.html
Transverse Mercator Projections and USGS Digital Products.
An explanation of why DRGs "tilt" when displayed on a computer screen.
(141K) | PDF
Datum Shifts and Map Coordinate Displays.
An explanation of why a datum conversion appears to cause a much greater shift in the UTM grid than in the latitude/longitude graticule.
Other Technical Information
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